Build a modal. A button opens it. The close button, a click on the backdrop, and Escape close it. A click inside the dialog does not close it. After closing, focus returns to the open button. Requirements: ✓ The backdrop handler checks that the click target is the backdrop itself ✓ Escape closes the dialog only while it is open ✓ The dialog shows Hack Frontend Acceptance criteria: ✓ A click inside the dialog keeps it open ✓ A click on the backdrop closes it ✓ Escape closes it and does nothing when it is already closed